Eyebrella

It sits in the helmet slot and parks a small rain cloud over your head that drizzles constantly. No damage, no buff, no shelter from actual weather. This is a mood piece.

• The rain takes its color from whatever water is in the biome you are standing in, and an active water fountain changes it too. Dye in the helmet slot has no effect on it.
• In the Aether the effect stops entirely.
• Flip gravity, stand on a step stool, or ride the Hand of Creation and the cloud ends up in the wrong place relative to your head.
• Worn in the functional helmet slot rather than the vanity one, the cloud draws above whatever vanity hat you have on, so you can combine it with another look.

Deerclops drops it, and the tooltip is lifted from a Don't Starve character examining the same item, which is where the whole crossover comes from.